The following commands work.

sed -i "/BC_CD23.BC_B.BC_A1.N1_C/s/CELL4WL_4BL_3/CELL4WL_4BL_1/g" s1*M8*
sed -i "/BC_CD23.BC_B.BC_A1.N0_C/s/CELL4WL_4BL_3/CELL4WL_4BL_1/g" s1*M8*

This command doesn't work.

sed -i "/BC_CD23.BC_B.BC_A1.N*_C/s/CELL4WL_4BL_3/CELL4WL_4BL_1/g" s1*M8*

How do I use wildcards in patterns?

  • 1
    There is a difference between wildcards as used in file name matching/shell globbing and the much more powerful regular expressions as used in sed (or grep and others). You should perhaps read an introduction. – Philippos Nov 6 '17 at 8:05
  • Thanks. I went through the link. I need to study regex in more detail . – Roopak Vasa Nov 12 '17 at 14:18

how to use wild card in pattern

In your particular case, N* means "match N char zero or more times".
If the pattern implies single N char and one(or more) following digits - that pattern part should be N[0-9]\{1,\}.
Besides, .(period) char matches any character, including newline (though newlines won't occur in the input here). To be matched literally it should be escaped \.
Thereupon, the main pattern would look as /BC_CD23\.BC_B\.BC_A1\.N[0-9]\{1,\}_C/


  • While your answer is perfectly correct and complete, I'm afraid that someone asking such a question has never heard of regular expressions and needs to be taught some basics to avoid being completely confused by this information. – Philippos Nov 6 '17 at 8:10
  • Thanks a lot. What does "\{1,\}" mean in regex ? – Roopak Vasa Nov 12 '17 at 14:21
  • @RoopakVasa, \{i\} As *, but matches exactly i sequences (i is a decimal integer; for portability, keep it between 0 and 255 inclusive). – RomanPerekhrest Nov 12 '17 at 14:53
  • \{4,7\} is for minimum 4 times, maximum 7 times the expression before. You can leave away either value, so \{,7\} is between zero and seven times and, as in your question, {1,\} is one or more times. Some sed versions have the shortcut \+ for that. – Philippos Nov 12 '17 at 16:34

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